Frontend Engineer

PayPay is looking for a Frontend Engineer to build and scale UI/Product experiences for our web applications. You'll work closely with Product, Design, and Backend teams to deliver high-quality features, contribute to a growing design system.

Primary Responsibilities

• Deliver product features end-to-end: translate requirements into clean, scalable UI implementations with well-structured components and predictable data flow
• Build reusable UI components and patterns: contribute to and extend our design system using tools like Storybook; prioritize consistency, accessibility basics, and developer ergonomics
• Integrate APIs and handle real-world states: implement robust data fetching patterns (pagination, caching, retries), and manage loading/error/empty states with clear UX behavior
• Write maintainable, modular code: apply good separation of concerns (presentation vs business logic vs API layer), meaningful abstractions, and clear naming; keep codebase easy to extend
• Optimize performance and reliability: identify bottlenecks (rendering, network, bundle size), apply pragmatic improvements (memoization, debouncing, virtualization where relevant), and avoid async pitfalls (stale responses, race conditions)
• Improve engineering quality: participate actively in code reviews, raise the bar on standards, and help enforce best practices around testing strategy, i18n, and build tooling
• Collaborate cross-functionally: work closely with PM/Design/Backend to clarify requirements, propose tradeoffs, and deliver iteratively with high ownership
• Support operational excellence: use observability tooling (e.g., Sentry, New Relic, Kibana) to debug production issues, measure impact, and improve stability
• Grow toward full-stack ownership (optional path): partner with backend teams and gradually take on BFF/API contributions using Node.js (NestJS/Express) as needed

Tech Stack

• Frontend: Typescript/Javascript , React/Vue, single-spa, Webpack, Jest, Storybook, i18n , micro-frontend
• Middlewear : NestJS, Express
• Infra/CI: AWS, Docker, Kubernetes, ArgoCD, Terraform, GitHub Actions, Jenkins
• Obs/Analytics: Sentry, Kibana, New Relic, Google Analytics, Firebase

Qualifications

• 3- 5 years of professional frontend development experience.
• Strong JavaScript fundamentals
• Solid experience in React and/or Vue
• Proven ability to write readable, modular, production-quality code
• Strong problem-solving skills with practical DSA (web-relevant) comfortable reasoning about time/space complexity
• Performance awareness: can identify bottlenecks and implement pragmatic optimizations
• Ability to do low-level design (LLD) for frontend features: break down requirements into components/modules, define interfaces, and plan implementation in milestones
• Good communication: can explain approach and tradeoffs clearly
• Leverage AI/LLM based tools in daily workflows

Preferred Qualifications

• Experience with Nest.js (routing, SSR/CSR tradeoffs, data fetching strategies)
• Experience with Node.js or API integration patterns (REST, pagination, auth flows, error handling)
• Familiarity with design systems, accessibility basics, and responsive UI patterns
• Exposure to frontend observability (error logging, basic performance metrics)
• Experience with micro-frontends (e.g., single-spa) or large-scale frontend architectures

What success looks Like

• You can independently deliver a feature end-to-end with clean architecture and reliable async handling
• Your code is modular, maintainable, and performance-conscious.
• You contribute to consistent UI patterns and raise team quality through reviews and collaboration.